Individuals are increasingly using the Internet to conduct financial and other sensitive transactions. For example, an individual might visit a bank website to check balance information or transfer money between accounts. Unfortunately, a variety of techniques are available to criminals and others with nefarious motives who wish to eavesdrop on or otherwise compromise the security that the individuals believe protect their transactions. As one example, unsuspecting users can be tricked into visiting a compromised or otherwise illegitimate copy of a legitimate website. As another example, the communications between the user and the legitimate website can be intercepted. Such communications can be intercepted even when protections such as TLS are employed, through the use of man-in-the-middle and other attacks.